单选题 Our factory produces millions of shoes every year, 30% ____ are sold abroad.

单选题 We had to ____ our trip because of the heavy storm.

单选题 It was not until the teacher came in ____ the students stopped talking.

单选题 After a long time of research, our report ____ to be true.

单选题 ____ I talked to Susan, I knew she wasn't the woman I wanted to marry.

单选题 It was ____ to us all ____ he paid no attention to his homework.

单选题 By the time we got to the railway station, the train ____.

单选题 Your parents will not let you go out alone ____ they are sure you are safe.